1. Field of the Invention
The present invention relates to a chip device such as a chip resistor device and a manufacturing method therefor, in which the high density is easily realized. More specifically, the present invention relates to a chip device and a manufacturing method therefor, in which the resistivity of the chip resistor device is constantly maintained even without using silver for lowering the self resistance in portions other than the upper electrode, thereby curtailing the manufacturing cost of the chip resistor.
2. Description of the Prior Art
At present, the chip resistor devices are widely used, and the reason is to realize a high density of the electronic parts, and to make the product light, simple and miniature. In the field of resistors, the use of the chip resistor device tends to be drastically increased.
A conventional chip resistor device is disclosed in U.S. Pat. No. 5,815,065 (dated Jan. 6, 1997), and this chip resistor device is illustrated in FIGS. 1 and 2.
As shown in FIGS. 1 and 2, upon a chip substrate 110, there are printed an upper electrode 122 and a resistance film 130. Upon the resistance film 130 and the upper electrode 122, there are printed two coating layers 140a and 140b so as to protect the resistance film 130, and there are also printed a pair of auxiliary upper electrodes 122a each having a cut portion C so as to make it possible to easily adjust the resistance characteristics of the chip resistor device 100. On each of the both side faces of the chip substrate 110, there is formed a side electrode 124, while a terminal electrode 150 is formed on each of the side electrodes 124.
Thus, if a power is supplied through a circuit pattern, the power passes through the terminal electrode 150, the side electrode 124, the auxiliary electrode and the upper electrode 122a and 122, and the resistance film 130, thereby determining the resistance characteristics of the chip resistor device 100. Particularly after and during the manufacture, the total resistance value of the chip resistor device can be precisely adjusted by means of the cut portion C of the auxiliary upper electrode 122a. 
In this conventional chip resistor device 100, as shown in FIGS. 1 and 2, the total resistance value can be adjusted after and during the manufacture of the chip resistor device 100 by means of the cut portion C of the auxiliary upper electrode 122a as described above. However, the power which is supplied from the circuit pattern of the circuit board passes through the terminal electrode 150, the side electrode 124, the auxiliary upper electrode 122a, the upper electrode 122 and the resistance film 130. Therefore if the resistivities of the respective electrodes are high, the resistance characteristics become defective. As a result, a large amount of silver (Ag) which shows the least resistivity has to be used, and this causes an increase of the manufacturing cost.
The present invention is intended to overcome the above described disadvantages of the conventional technique.
Therefore it is an object of the present invention to provide a chip resistor device and a manufacturing method therefor, in which a portion directly contacting to a terminal electrode (contacting to a circuit board) is necessarily provided so as to form a perfect bypass signal supply path. Thus electrodes other than the upper electrode can be made of materials other than silver, and therefore, the manufacturing cost for the chip resistor device can be decreased.
In achieving the above object, the chip device according to the present invention includes: a chip block having an upper face and a pair of mutually oppositely facing side faces; an electrode part having an upper electrode formed on the upper face and on the side faces of the chip block, and having a side electrode formed on the side faces of the chip block; a special electrical property layer connected to the upper electrode of the upper face of the chip block; at least one or more protecting layers formed upon the special electrical property layer to protect it; at least one or more terminal electrode layers formed on the electrode part of the chip block, and solder-connected to a circuit pattern of a circuit board; and a terminal connection part formed on the surface of the upper electrode to be directly connected to the terminal electrode at least at one point.
In another aspect of the present invention, the method for manufacturing a chip device according to the present invention includes the steps of: preparing an alumina substrate; screen-printing a plurality of lower electrodes on a lower face of the round alumina block in accordance with standards of chip resistors, and baking the lower electrodes; screen-printing a plurality of upper electrodes on an upper face of the alumina substrate in accordance with standards of chip resistors, and baking the upper electrodes; printing special electrical property layers on an upper face of the alumina block so as to be connected to the upper electrodes, and baking them; printing at least one or more protecting layers with a certain width upon the special electrical property layer to protect it by using a glass material, and baking them; breaking the alumina substrate in a lateral direction into a plurality of pieces to form a pair of mutually oppositely facing side faces, and carrying out a dipping process to print side electrodes of a certain length on the side faces of the pieces thus cut so as to form terminal connection parts contacting at least at one point to the upper electrodes, and baking them; and breaking the pieces (thus laterally cut) in a longitudinal direction to form a plurality of chip blocks, and carrying out a plating process to make a terminal electrode directly connected to the upper electrode at least at one point through the terminal connection part.